Calibration is an important process in any measurement technique: the higher the precision of calibration, the better are the measurement results, i.e. the higher the measurement system sensitivity to small measurement variations.
The RF calibration procedure is aimed at correcting measurement errors, thus ensuring that the response of a device under test (DUT) is recorded correctly. According to the conventional techniques of the kind specified, a vector network analyzer (VNA), including a signal transmitter/receiver, is frequently used; calibration loads are measured when connected to the appropriate signal ports of the VNA, such connection being carried out each time the calibration is to be performed. A calibration device includes a set of calibration loads or terminals with known loads. The calibration consists of switching (manually or automatically) between the calibration loads for sequentially measuring the response of the VNA for each of these loads, and by this determining how the signal propagation between the signal transmitting/receiving plane and the DUT connection plane is affected by a signal transmitting media in between these planes. Upon completing the calibration procedure, the calibration device is replaced by the DUT.
Some examples of the calibration procedure of the kind specified are described in U.S. Pat. No. 5,434,511 and U.S. Pat. No. 6,914,436.